1. Field of the Invention
The present invention relates to semiconductor lasers. Specifically, the present invention is concerned with the prevention of catastrophic optical damages (COD) on semiconductor lasers that occur during a continued high power operation.
2. Description of the Related Art
It is generally known that semiconductor lasers of heterostructure such a AlGaAs and AlGaInP are vulnerable to a catastrophic optical damage of their front office due to increased surface temperature which is caused by localized absorption of light The amount of light absorbed at the front face increases with surface oxidation and increased number of lattice defects. Since an increase in surface temperature causes a narrowing of the forbidden band in the neighborhood of the front face, a vicious circle of increasing temperature begins, which finally results in a fused front face, A number of window facet structures have been developed to solve this problem by using materials of high transmissivity. However, these window facet structures are very complex and their productivity is low.